Veterinary Pathology Research Articles

Meet the First Authors.

Meet the First Authors.

Image Challenge in Veterinary Pathology, Answers: Foreign bodies.

Image Challenge in Veterinary Pathology, Answers: Foreign bodies.

Image Challenge in Veterinary Pathology.

Image Challenge in Veterinary Pathology.

Pathologists' perspective on the study design, analysis, and interpretation of proliferative lesions in lifetime and prenatal rodent carcinogenicity bioassays of aspartame.

Aspartame, an artificial sweetener commonly used as a sugar substitute, is currently authorized for use in more than 100 countries. Hundreds of studies, conducted in various countries dating back to the 1970s, have shown that aspartame is safe at real-world exposure levels. Furthermore, multiple human epidemiology studies have provided no indication that consumption of aspartame induces cancer. Given the continued controversy surrounding the Ramazzini Institute's (RI) studies suggesting that aspartame is a carcinogenic hazard in rodents and evaluation by the International Agency for Research on Cancer, this report aims to provide the perspective of experienced pathologists on publicly available pathology data regarding purported proliferative lesions in liver, lung, lymphoid organs, and mammary gland as well as their implications for human risk assessment as reported for three lifetime rodent carcinogenicity bioassays of aspartame conducted at the RI. In the authors' view, flaws in the design, methodology and reporting of the RI aspartame studies limit the utility of the data sets as evidence that this agent represents a carcinogenic hazard. Therefore, all three RI studies, and particularly the accuracy of their pathology diagnoses and interpretations, should be rigorously reviewed by qualified and experienced veterinary toxicologic pathologists in assessing aspartame's carcinogenic risk.

A Muskrat (Ondatra zibethicus) with alveolar echinococcosis bitten to death by a dog – a challenge for the forensic pathologist as an expert witness

We present a case that illustrates the complex contexts in which forensic veterinary pathology examinations may be carried out. A wild muskrat (Ondatra zibethicus) had died after a putative bite attack from a domestic dog. Bite attacks by privately owned dogs on wild animals in Switzerland violate the Swiss civil (and/or hunting) laws, and dog owners are generally punished with a monetary fine; hence, this case appeared to be straightforward. However, the results of the subsequent post-mortem examination of the muskrat not only confirmed the presence of injuries related to the bite attack, but also detected alveolar echinococcosis (ie, infestation with Echinococcus multilocularis). Therefore, as an intermediate host of the parasite, the muskrat could have contributed to further spread of a severe helminthic zoonosis had it not been killed by the dog. It was probably an easy prey for the dog as it probably had been weakened by the disease. Furthermore, muskrats are considered as pests and invasive species, and are non-indigenous huntable game in Switzerland and other European countries in which programmes for the prevention of their further spread and endangerment of native wildlife are established. The role of the forensic veterinary pathologist in such a complex scenario is to adopt an unbiased approach and establish the facts, which in this case was to determine the cause of death and suspected perpetrator, identify any concomitant and/or underlying diseases and consider potential animal welfare issues.

A retrospective histopathological survey on canine lymphomas subtypes of Porto District.

Lymphomas are dogs' most common hematopoietic neoplasms and represent a heterogeneous group, as occurs in humans. Considering the role of dogs as models of human lymphomas and the geographical correlation of the cases of canine and human lymphoma, it is important to continuously assess the epidemiological distribution of lymphoma subtypes in dogs. This study aimed to provide a survey of canine lymphoma subtypes diagnosed from 2005 to 2016 in the academic veterinary pathology laboratory of the University of Porto. A total of 75 canine lymphomas diagnosed by histopathology in the Porto district were included. All cases were immunophenotyped by CD3 and PAX5, classified according to the current classification WHO and coded with Vet-ICD-O-canine-1. Mixed breed dogs were most common (28%), followed by Cocker Spaniels (12%), Boxers (9%), and Labrador Retrievers (6%). The mean age was 9.2 years (SD = 3.3) (10.7 years for small, 8.9 years for medium and large, and 5.7 years for giant breed dogs, p < 0.05). Regarding sex, there was no difference in frequencies or mean age. B-cell lymphomas were more common (57.4%) than T-cell lymphomas (37.3%), and 5.3% were classified as non-B/non-T-cell lymphomas. Of the cases, 49% had a multicentric distribution, followed by splenic (22%), cutaneous (12%), alimentary (12%), and extranodal (3%) forms. The most common B-cell subtypes were diffuse large B-cell lymphoma (DLBCL) (16.3%) and large immunoblastic lymphoma (14%), while T-zone lymphoma (21.4%) and intestinal lymphoma (18%) were the most common T-cell lymphoma subtypes. Our study shows that the Porto district follows the international trend of higher prevalence of B-cell lymphomas in dogs, especially of the DLBCL subtype.

Immunohistochemical localisation of Glutamate ammonia ligase (GLUL) in cerebrum in different clinical forms of canine rabies

Rabies, one of the earliest known diseases reported in the history of mankind, is a fatal acute viral disease of the central nervous system. Despite numerous studies on etiology of rabies, its exact mechanism of neuropathogenesis remains unidentified. Glutamate ammonia ligase (GLUL) is a protein present in brain which play an important role in the pathogenesis of many neurological conditions. GLUL was identified to be over expressed in brain of human rabies. Cerebral cortex is the part of brain primarily responsible for coordination of movements and behaviour in animals and humans. Hence the work was designed to study the immunohistochemical localisation of GLUL in cerebrum in rabid carcasses in order to elucidate its role in the pathology of this deadly viral infection. The carcasses of 219 rabies suspected dogs that were brought to the Department of Veterinary Pathology, CVAS, Mannuthy, for necropsy between January 2021 and August 2022 formed the materials for the study. One hundred and thirty-three cases were found positive for rabies using the gold standard test for rabies - Direct Fluorescent Antibody Test (dFAT) which was further confirmed by polymerase chain reaction targeting N gene with amplicon size 533 bp. Among these 133 confirmed cases, 30 selected samples (frontal, occipital, temporal, parietal lobes of cerebrum) were further processed for histopathological and immunohistochemical (IHC) studies. The IHC signals of GLUL obtained were compared with the clinical form of rabies. Immunohistochemical staining revealed localisation of GLUL in glial cells with different staining intensity in encephalitic and paralytic form of rabies. The study concluded that the IHC signals for GLUL were stronger for furious form of rabies and weak for dumb form of the disease.

Thyroid pathology in canine parvoviral infection

The hypothalamic-pituitary-thyroid axis is suppressed by pro-inflammatory mediators in systemic disease, which affects the thyroid hormone level. Canine parvovirus is one of the important infectious diseases which causes profound morbidity as well as mortality in dogs. It is found that canine parvovirus infection can result in non-thyroidal sickness syndrome. The relation between thyroid pathology and canine parvovirus infection will pave the way for therapeutic and preventive measures for this infectious disease. This study was conducted on 61 dog carcasses brought to the Department of Veterinary Pathology, College of Veterinary and Animal Sciences, Pookode during one year period. Among 61 cases, nine were found to be positive for canine parvovirus which constitutes an incidence of 14.75 per cent. Analysis of gross and histopathological lesions in canine parvovirus positive cases was the goal of this investigation. The gross lesions observed were paleness and nodular growth and histopathological lesions encountered were lymphocytic thyroiditis, colloidal goiter, c cell hyperplasia, severe fibrotic changes and neoplastic lesions. Further research is required to understand the pathophysiology of the euthyroid sick syndrome in canine parvoviral infection.

Outbreak of Marek’s Disease in Chicken Flocks with Uncommon Pattern of Gross Lesions

Marek’s disease is one of the highly contagious and oncogenic diseases of poultry that remains as a threat to the fast-growing poultry sector, even after proper vaccination. Generally, the disease is identified incidentally during the routine postmortem examination as nerve enlargement or as gross tumor lesions. The present article discusses the outbreak of Marek’s disease in three vaccinated commercial layer flocks with high mortality and subtle gross nodular lesions. Three to fivemonth- old, commercial layer chickens from three different farms were submitted for post mortem at Department of Veterinary Pathology, College of Veterinary and Animal Sciences, Pookode, Kerala with the history of weight loss and mortality rate of about 25 per cent. On postmortem examination, the carcasses revealed severe emaciation and atrophied to mildly enlarged visceral organs in the majority of cases except in three birds with small white nodules. Microscopical examination revealed, varying degrees of pleomorphic lymphoid cell proliferation in the liver, spleen, kidney, ovary, pancreas and thyroid. Polymerase chain reaction targeting gB gene confirmed the presence of Marek’s disease virus (MDV) in birds, with and without gross tumors. The birds from farms of different flock size showed similar high mortality rate but mostly without gross tumour lesions of MD. These findings emphasise the importance of histopathological examination in routine postmortem of chickens to identify diseases with gross nonspecific lesions.

Unilateral testicular atrophy and epididymal lithiasis in a Gramasree rooster

Testicular atrophy is a condition impairing the reproductive health of male chicken. Lithiasis or stone formation in testicles or epididymis adds to the gravity of the problem. The present study describes a case of unilateral testicular atrophy with epididymal lithiasis in a one-year-old male Gramasree cock. The carcass, was brought to the Department of Veterinary Pathology, College of Veterinary and Animal Sciences, Pookode, for postmortem examination. The lesions were recorded and tissues for histopathology were collected in 10% neutral buffered formalin, sectioned, and stained using routine hematoxylin and eosin staining procedure. Grossly, there was diffused congestion of the testicular tunic with atrophy of right testis. The epididymis was congested with multifocal white spots. Histologically, seminiferous tubules were severely degenerated. The efferent ductules of epididymis were dilated with basophilic amorphous and granular liths in multiple locations. Sperm stasis was evident in a few ductules and rete testes. The lith formation might have caused sperm stasis and degeneration and atrophy of the testis.

Chronological transition of necropsy cases of animals in Tokyo, Japan.

There is no nationwide necropsy database of animals in Japan, and most of the records are available from the postwar period. To clarify the chronological transition of animal necropsy cases in Tokyo, Japan, the records accumulated in The University of Tokyo from 1902 were investigated. Of necropsy records on paper or electronic from 1902 to 2021 kept at the Laboratory of Veterinary Pathology, The University of Tokyo, totally 3,137 cases including 572 in 1903-1914 (the Meiji-Taisho period), 1,258 in 1956-1969 (the Showa period) and 1,307 in 2006-2020 (the Heisei-Reiwa period), respectively, were examined for species, breed, age and pathological diagnosis. Dogs (44.6%) and horses (34.8%) in the Meiji-Taisho period, dogs (62.9%) and cats (17.3%) in the Showa period, and dogs (46.0%), cats (26.1%) and exotic animals (20.5%) in the Heisei-Reiwa period were the most necropsied animal species. With the passage of time, the number of animal species increased, and the breeds of dogs and cats came to be more various. The median ages of death were 2 years, 3 years and 10 years old in dogs in the Meiji-Taisho, Showa and Heisei-Reiwa periods, respectively, and 2 years and 10 years old in cats in the Showa and Heisei-Reiwa periods, respectively. Viral, bacterial and parasitic infections were decreased, and inversely tumor cases increased due to the prolonged lifespan.

Diagnostic challenge in veterinary pathology: Pruritus in a dog with a mixed cellular infiltrate.

Diagnostic challenge in veterinary pathology: Pruritus in a dog with a mixed cellular infiltrate.

Spontaneous splenic hemangiosarcoma in pet guinea pigs (Cavia porcellus): five cases (2007–2021)

Spontaneous hemangiosarcoma in guinea pigs has only been reported twice in the literature. This study aims to better characterize the prevalence, clinical presentation, treatment, and outcome of this rare disease in guinea pigs. Medical records (2007–2021) from four referral centers were reviewed. Guinea pigs with a histopathological diagnosis of hemangiosarcoma performed by a board certified veterinary pathologist were selected for inclusion. Of 3994 guinea pigs examined, five were included in the study. The median age at the time of diagnosis was four years (4–6 years). Four of the five patients presented with dysorexia. An abnormal spleen was palpated in all animals and confirmed by ultrasonography. Only one guinea pig had presurgical radiographs to evaluate for metastasis before splenectomy. One patient was euthanized after surgery, while the others died two weeks, six months, 15 months and 49 months after the procedure. One patient was also treated with Trametes versicolor extracts as an adjuvant antineoplastic therapy. The median survival time was six months. Abdominal palpation and ultrasound can provide a presumptive diagnosis of splenic enlargement. Splenectomy has proven to be a feasible surgical procedure for the treatment of splenic hemangiosarcoma, potentially combined with adjuvant anticancer therapies. The variable survival after splenectomy reported in the five cases here is challenging to interpret because of the different anesthetic techniques and comorbidities. Further research is needed to improve understanding of the biological behavior of this neoplasm as well as the benefits of splenectomy and adjuvant therapies.

Multiple Choice Questions Versus Very Short Answered Questions in the Evaluation of Students of Veterinary Pathology

Background: Well-developed assessment methods have a positive impact on students’ performance, and higher education institutes are usually encouraged to establish and use effective assessment methods that effectively enhance the learning process. Objectives: This study was designed to compare students’ performance in multiple choice questions (MCQs) including best single answer (BSA) and multiple true and false (MTF) types, and very short answer (VSA) questions, and to evaluate gender differences and feedback from students and faculty. Materials and methods: A test containing three different types of questions, BSA, MTF and VSA questions (10 each), was delivered to eight groups of veterinary pathology students (3rd level, Faculty of Veterinary Medicine, Assiut University, Assiut, Egypt) in April 2022. Students’ performance, test reliability and gender differences as well as feedback from students and faculty were evaluated. Results: Students did a significant higher performance in BSA and MTF questions compared to VSA questions. The reliability of BSA, MTF and VSA questions between different groups of students were 0.53, 0.52 and 0.13, respectively. Girl students achieved a higher performance in the whole test compared to boy students. Both boy and girl students showed nearly similar performance in BSA and MTF questions. However, girl students got significant higher score in VSA questions compared to boy students. Students’ and faculty opinions were in favor of BSA and MTF questions. Conclusion: Students did much better in MCQs than VSA questions. BSA and MTF questions are preferentially favored by students and faculty.

Pneumoencéfalo intraventricular em cão: relato de caso

Pneumocephalus is a well described disease; it is commonly diagnosed in humans, but the condition is rarely encountered in veterinary medicine. Computed tomography (CT) is the gold-standard diagnostic method for identifying this disease, and other methods (such as necropsy) are rarely described. In this report, we describe necropsy findings of a 10-month-old, mixed-breed dog with intraventricular pneumocephalus. The dog was referred to Laboratory of Animal Pathology of the Federal University of Uberlândia, Brazil, for necropsy after being diagnosed with pneumocephalus upon CT. In the examination, the brain had dilation of both lateral ventricles with empty spaces. Histopathology showed congestion and mineralization only near the lateral ventricles, leading to the diagnosis of pneumocephalus based on the macroscopic findings. The animal also showed sinusitis characterized by nasal discharge and neutrophilic infiltration of nasal sinuses. However, bacterial culture was not conclusive because of contamination of the sample. This is therefore an important report that shows necropsy findings of intraventricular pneumocephalus, which is a rare condition in dogs. By documenting the necropsy findings, we hope to help veterinary pathologists, including those with limited access to diagnostic imaging.

Call to Brazilian Ichthiopathologists – The Brazilian Ornamental Fishes Needs You!

Since fish have potential to grow as pets in this market in Brazil it is interesting to seek another approach of investigation about the diseases that affect these animals. The Ichthiopathologist is the veterinary pathologist who is more interested or specialized at fishes. This professional can bring another look to the ornamental fish chain, since they can focus at microcosms and then make the clinical correlation. Here we list the literature you need to have to follow this profession safely and enhance the entire productive range of Brazilian ornamental fish.

Retrospective Analysis of 101 Canine Lymphoma Cases Diagnosed in Surgical biopsies in Latvia (2011–2020)

Abstract Lymphoma is a malignant tumor commonly diagnosed in dogs representing 7–24% of all canine tumors. There has been no previous studies focused on characterization of canine lymphoma cases in Latvia. The goals of this retrospective study were to determine prevalence and characteristics of lymphoma cases among biopsy submissions to a private veterinary pathology service that receives approximately 80% of all biopsy submission in Latvia and to compare this data with published canine lymphoma reviews. Data were retrieved to select records from Latvian dogs diagnosed with lymphoma between 2011 and 2020, determining characteristics of dogs and types of lymphoma based on anatomic distribution and cellular morphology. In a ten-year study period, diagnosis of lymphoma constituted 1–4% of surgical biopsy submissions each year without upwards trend. Affected dogs were middle age (median 8 years; range 2–13), with a slight male predominance (58%). The majority of dogs (19%) were mixed breed. Top 3 affected dog breeds were Rottweiler, American Staffordshire terrier and French bulldog with 6–7 cases in each breed. Multicentric form of lymphoma predominated (55%) followed by alimentary and mucocutaneous lymphoma (21% and 14%, respectively). Within multicentric form of lymphoma two thirds were intermediate to large cell lymphomas. Included in this group would be diffuse large B cell lymphomas, the most common subtype of canine lymphomas; however, lack of immunohistochemical testing precluded complete lymphoma classification according to WHO guidelines. Results of this study correlate well with the previously published results and provide important information to Latvian small animal veterinarians and pathologists.

Hydrogel treatment for idiopathic osteoarthritis in a Dunkin Hartley Guinea pig model.

The study objective was to determine if intraarticular injections of an extracellular matrix (ECM) powder and blood composite (ECM-B) would have a significant impact on post-operative gait parameters without eliciting adverse cartilage changes or severe lymphatic reactions in an idiopathic osteoarthritis (OA) model. Twenty-one Dunkin Hartley Guinea pigs received an intraarticular injection of ECM-B in each knee and were split into sub-groups for gait assessment and post-harvest knee evaluations at 1 week (n = 5), 2 weeks (n = 5), 4 weeks (n = 5), or 8 weeks (n = 6). The results were compared with a control group (n = 5), which underwent bilateral injections of phosphate-buffered saline (PBS), gait measurements at 1, 2, 4, and 8 weeks, and post-mortem knee evaluation at 8 weeks post-injection. Hind limbs and popliteal lymph nodes were collected at the Week 8 endpoint and underwent histological analysis by a veterinary pathologist. Significant improvement in hind limb base of support was observed in the ECM-B group compared to the control group at Week 4 but was no longer significant by Week 8. No significant differences were observed between control and ECM-B groups in hind limb cartilage, synovium, or popliteal lymph node histology at Week 8. In conclusion, administration of an ECM-B material may improve gait for a limited time without significant adverse effects on the cartilage, synovium, or local lymph nodes.

A jakobsian analysis of communication in veterinary anatomic pathology

Since I figured out that anatomic pathology is communication, I got interested in this subject and If I'am assuming myself as a communicator, then, I logically need to study and understand it. When I looked for this, Jakobson's explanation was the most elegant, eloquent and simplest explanation I've found. If you doubt me, just search for this in youtube, there are a lot of animated videos about it. So, Jakobson divides communication in six crucial points: adresser, message, addressee, context, code and channel. The adresser is the person who will write and send the message to the addressee, the receptor, the person who will read it. The context is what the message is about and the code is the language used. Finally, the channel is the physical channel, a way where the message is write, it may be a paper or a video or any other. Keep in mind that those points are not always isolated from each other, they are frequently overlapped, and this is just a didactic organization, that is much more easily to understand in a fluxogram.

Primary Tracheal Squamous Cells Carcinoma in a Dog

Primary tracheal neoplasms are uncommon and poorly documented in veterinary medicine, being most frequently reported in domestic cats. Squamous cell carcinoma (SCC) is a malignant neoplasm that originates from the stratified squamous epithelium, considered one of the most common skin neoplasms in dogs and cats. This paper aims to report the anatomopathological and immunohistochemical findings of a clinical case of primary SCC in the trachea of a female Schnauzer canine, attended at the Veterinary Hospital Luiz Quintiliano de Oliveira of the Faculty of Veterinary Medicine of Araçatuba (FMVA – UNESP), complaining of choking, coughing and dyspnea for 1 month. The tracheal portion affected by the neoplasm was sent to the Veterinary Pathology department of the FMVA after surgical excision. Fragments of the neoplasm were collected and fixed in 10% formaldehyde for further histopathological and immunohistochemical analysis. Microscopically, the neoplasm was well differentiated, being characterized by the presence of keratin pearls, low degree of pleomorphism and rare mitotic figures. In the immunohistochemical analysis, there was immunoexpression of anti-cytokeratin antibodies AE1AE3, 34BE12, CK14 and CK5/6, confirming the diagnosis of squamous cell carcinoma. In about 30% of the cells there was immunostaining for Ki67 antibodies, justifying the low mitotic index of tumor cells and the few images of mitosis seen. Due to the rare occurrence of primary tracheal SCC in dogs, the use of diversified diagnostic techniques is important in order to better understand the biological behavior of this neoplasm in unusual anatomical locations.